Excimer laser eye surgery system

ABSTRACT

A compact excimer laser system is provided that includes argon fluoride laser gas, electronic, and laser head all compactly arranged such that the patient bed can rotate over all of these components. This allows the patient bed to be rotated for easy egress of the patient without striking the head against an optical extension through which the excimer laser is fired onto the patient&#39;s eye. Further, an automated lamellar keratoplasty system is incorporated into the electronics and components of the laser system so that laser in situ keratomileusis can be easily performed.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The invention relates to laser systems for eye surgery, and moreparticularly to a compact excimer laser eye surgery system particularlysuited for laser in situ keratomileusis.

[0003] 2. Description of the Related Art

[0004] Since the invention of spectacles, doctors and scientists havestriven to improve human vision. From eye glasses, to contact lenses, toradial keratotomy, doctors have sought more convenient and permanentsolutions to defective vision.

[0005] The development of the excimer laser provided a uniqueopportunity for vision correction. The excimer laser, especially anargon fluoride excimer laser operating at a 193 nanometers, removestissue through a non-thermal process of “ablation” in which themolecular bonds of tissue are literally broken. This allows preciseamounts of tissue to be removed without heating the surroundingtissue-heating that can bum that tissue leading to scarring. Thisablative process using the excimer laser has been employed in a numberof ways to literally reprofile the surface of the eye. These techniquesare described, for example, in Assignee's U.S. patent application Ser.Nos. 08/338,495, filed Nov. 16, 1994, and 08/324,782, filed Oct. 18,1994, which are hereby incorporated by reference.

[0006] These techniques have been taken a step further through thedevelopment of laser in situ keratomileusis (LASIK), a technique inwhich the surface layer of the eye is resected, and the underlyingstromal tissue is removed using this laser ablation technique. Thatsurface layer is then replaced, and the epithelium then regrows, holdingthe surface layer in place. This technique has been patented by GholamPeyman in U.S. Pat. No 4,840,175, which is hereby incorporated byreference.

[0007] Both of these techniques, however, benefit from efficient andcompact workstations. These techniques generally should be performed insurgical quality clean rooms. Such clean rooms tend to be expensive, soany reduction in the amount of space taken by an excimer laser surgerysystem would be beneficial. Further, devices providing an integration offunctionality and an increase in efficiency are also greatly desirable.

SUMMARY OF THE INVENTION

[0008] Therefore, according to the invention, an excimer laser system isconstructed in a highly compact form, in which a patient bed forms anenclosure in which is placed the gas bottle for the excimer lasersystem, typically holding argon fluoride gas, along with electronics forpowering and controlling the excimer laser system. Further, the patientbed enclosure can preferably be rolled away to allow easy access tothese components for maintenance and service.

[0009] The laser head is placed immediately adjacent to the bed, butbelow the height of the bed. The bed includes a bearing, allowing thebed to rotate over the laser head and away from an excimer laser opticalextension through which the laser beam is fired into the patient's eye.This allows the patient to sit up without striking his or her head.Further, the bed can be rotated 90°, allowing non-laser ophthalmicsurgery to be performed using the same equipment in the same clean room.

[0010] Further according to the invention, an automated lamellarkeratoplasty (ALK) system is integrated into the laser system, providingboth computer and monitoring and connections for a microkeratome. Twofoot switches are provided, one for advancing and retracting themicrokeratome, and the other for activating the vacuum to themicrokeratome. This integrated system allows an easily used andcontrolled system for performing laser in situ keratomileusis (LASIK).

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] A better understanding of the present invention can be obtainedwhen the following detailed description of the preferred embodiment isconsidered in conjunction with the following drawings, in which:

[0012]FIG. 1 is a perspective view of the laser system according to theinvention;

[0013] FIGS. 2A-C are top, side, and front views of the laser systemaccording to the invention;

[0014] FIGS. 3A-D are top, front, back, and side views of the patientbed enclosure and rotatable patient bed according to the invention;

[0015] FIGS. 4A-C are top, front, and side views of the equipmentenclosed by the patient bed enclosure of FIGS. 3A-D; and

[0016]FIG. 5 is a front view of the internal components of the system ofFIG. 1, further illustrating the incorporated automated lamellarkeratoplasty (ALK) system for performing LASIK.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0017] Turning to FIG. 1, shown is the laser system L according to theinvention. This laser system is preferably based on a 193 nmargon-fluoride excimer laser, but other lasers could be used. A patientbed enclosure 100 includes a patient bed 102 disposed on top of it. Aphysician workstation platform 104 is situated diagonally away from thepatient bed 102, and includes a keyboard 106 and control inputs 108. Thekeyboard 106 and control inputs 108 provide input to a computer systemthat in part controls the laser system L. That computer system providesdata for a display 110. The control inputs 108, the keyboard 106, andthe display 110, all in conjunction with the computer system, serve tocontrol the laser system L, and to fire an excimer laser beam through anoptics path that extends perpendicularly through the physicianworkstation enclosure 112, and then horizontally through an opticalextension 114. The source of the laser beam is an excimer laser headfound in a laser head enclosure 118. The optical extension 114 directsthe excimer laser to the patient's eye as the patient lies on thepatient bed 102, and also provides optics 116 for the physician to viewthe surgery before and while it takes place.

[0018] The optical extension 114 also includes an eye tracking systemwhich partially uses the optical path extending through the physicianworkstation enclosure 112. The eye tracking system preferably employs ahigh speed video camera and dedicated electronics, and works inconjunction with the computer system to maintain the laser opticsaligned with a desired point on the patient's eye.

[0019] The patient bed enclosure 100 also includes a foot rest 117 forthe physician to use during surgery. This foot rest 117 further includestwo foot switches 119 and 121, which control the vacuum and power to amicrokeratome in an automated lamellar keratoplasty (ALK) system used ina LASIK procedure. This is further discussed below in conjunction withFIG. 5.

[0020] Preferably, the eye tracking system also employs Transputer™boards manufactured by INMOS Limited used in conjunction with aTransputer Frame Grabber™ manufactured by Parsytech, GmbH, installed inthe computer system.

[0021] Turning to FIGS. 2A-C, shown are views of the system of FIG. 1. Atop view in FIG. 2A illustrates how the optical extension 114 extendssubstantially over a head portion 124 of the patient bed 102. Thephysician then uses the optics 116 to observe the surgery as it takesplace.

[0022] Also from this position, it is seen that adjacent to the patientbed 102 is the laser head housing 118. This laser head in the laser headhousing 118 fires the laser beam, preferably a 193 nanometer excimerlaser. This beam is fired parallel to the floor and then is reflectedvertically up through the physician workstation enclosure 112, and thenout through the optical extension 114. The laser beam is then reflecteddown into the patient's eye at a center point 120.

[0023] Turning to FIG. 2B, another view of the workstation is shown.From this view, a final beam path 122 is shown firing down from theoptical extension 114 towards a head portion 124 of the bed 102. It isalso seen that if a patient were to sit up, the patient could strike hisor her head on the optical extension 114. In FIG. 2B, it is seen thatthe laser head 118 does not extend above the patient bed 102. Thisfeature will be appreciated in conjunction with FIG. 3A discussed below.

[0024] Turning to FIG. 2C, shown is an end view, again showing the beampath 122 at which the excimer laser will fire onto the head portion 124of the bed 102. Also, it is seen that the height of the workstationplatform 104 is set so that the physician is provided easy access toboth the keyboard 106 and to the patient's head, which is resting in thehead portion 124 of the patient bed 102. FIG. 2C also shows a patientbed adjustment platform 125, which is part of the patient bed enclosure125. This adjustment platform 125 provides motorized control of thepatient bed 102 in the x, y, and z axes through the controls 108.

[0025] Turning to FIG. 3A, shown is the patient bed 102 in its rotatedposition. The patient bed 102 rotates on a bearing 126, which firmlyconnects the patient bed 102 to the patient bed enclosure 100. Thepatient bed 102 position is adjusted by motors and pulleys 140, whichprovide x, y, and z axes control of the adjustment platform 125.Further, the patient bed 102 rotates over the laser head 118.Preferably, the patient bed rotates sufficient so that the head portion124 of the patient bed 102 has rotated out from under the opticalextension 114. The patient can then sit up without striking his or herhead on the optical extension 114. Further, the patient bed 102 canpreferably rotate up to 90°, so that a single clean room could be usedfor performing both laser and non-laser ophthalmic surgery. In thisposition, not shown the doctor would operate on the patient's headlocated within a head portion 124 of the patient bed 102, but rotated90° away from the physician workstation platform 104. Further,preferably an electric solenoid 127 electrically latches into a latchinghole 128 on the patient bed 102, holding the patient bed 102 in placeduring surgery. By providing the laser head 118 below the surface of thepatient bed 102, the patient bed 102 can rotate over it.

[0026] Three more views of the patient bed 102 and the patient bedenclosure 100 are shown in FIGS. 3B, 3C, and 3D. FIG. 3B is an end viewfrom the perspective of the head portion 124 end of the patient bed 102,and shows that the patient bed 102 is mounted on rollers 129 and lockedinto place with stops 1130. In practice, the patient bed enclosure 100forms a cover that encloses a gas bottle holding argon fluoride gasneeded by the laser head, cooling components, and electronics needed bythe entire system. This is further discussed below in conjunction withFIGS. 4A-C.

[0027] The patient bed enclosure 100 is rolled over those components ina direction 131 and then locked into place with the stops 130 before thesystem is operated.

[0028]FIG. 3C illustrates a left (from a patient's perspective) sideview of the patient bed enclosure 100 and the patient bed 102.

[0029]FIG. 3D illustrates a bottom end view (from the patient'sperspective) of the patient bed 102 and the patient bed enclosure 100.As can be seen, an additional recess 132 is formed to accommodate thelaser head discussed below in conjunction with FIGS. 4A-C.

[0030] Given FIGS. 3A-D, it will be appreciated that there is an openspace formed underneath the patient bed enclosure 100. This open spaceis used to enclose the material necessary for the laser system L tooperate. By providing the patient bed enclosure 100 as the cover forthese components, the patient bed 102 and the patient bed enclosure 100can be easily rolled away from these components to allow easy access andservice. At the same time, using this enclosed space is an advantage insurgical systems because clean room operating space is a scarceresource. Therefore, a smaller and more compact system providesadvantages because it reduces then size of the clean room necessary.

[0031] Turning to FIGS. 4A-C, shown are block diagrams illustrating thearrangement of the components underneath the patient bed enclosure 100.Referring to FIG. 4A, shown is a gas bottle 200, electronics 202 forboth providing power and for providing the computer system for the lasersystem L, and an internal laser head 204. AC power components areprovided in the open space 203 left of the electronics 202. Theelectronics 202 include the computer system, the bed power supplies, andother system electronics, such as transformers and interface circuits.The internal laser head 204 is enclosed by the laser head enclosure 118,and forms a laser beam, preferably a 193 nanometer excimer laser beamthat fired a left to right in reference to the diagram of FIG. 4A Thelaser head 204 preferably includes an integral 30K volt power supply.Further included are various cooling components 206.

[0032] Referring to the end view of FIG. 4B, it is seen that the gasbottle 200 is mounted on rollers 208 for easy replacement of the gasbottle 200 after the patient bed enclosure 100 is rolled out of the way.Further, it is seen that the electronics 202 include a portion thatsurrounds the gas bottle 200, thereby more efficiently using the space.Again, the laser head 204 is shown, with beam egress points 210 and 212for providing the excimer laser beam which is then reflectedtransversely through the optical extension 114, which forms the finalbeam directing portion. That final beam directing portion then redirectsthe laser beams into the patient's eye. Further, the final beamdirection portion includes optics necessary to adjust the position thatthe excimer laser beam strikes the patient's eye. Also, an aiming laseris preferably provided in the optical extension 114 colinearly alignedwith the excimer laser. This preferably includes two aiming mirrors, onefor each axis.

[0033] Turning to FIG. 4C, a side view from the perspective as FIG. 3Cis illustrated of the internal components. Again, it is seen how theelectronics 202 wrap around the gas bottle 200.

[0034] Turning to FIG. 5, yet another view is shown. In this case, anALK, or automated lamellar keratoplasty system 300 is integrated intothe laser system L. Automated lamellar keratoplasty is a system used toassist in a LASIK procedure, or a laser in situ keratornileusisprocedure. This procedure requires a microkeratome, which preferablyincludes a vacuum port for providing suction for attachment to the eyeand a power port for providing a high speed oscillating movement of theblade. Once a flap is taken from the patient's eye as the patient's headrests in the bed 124, the flap is pulled back and tissue underneath isexcised, according to the technique described by Gholam Peyman in hispreviously incorporated U.S. patent.

[0035] Such systems, however, require monitoring and control, sopreferably the two foot switches 117 and 119 are provided for the ALKsystem 300. These switches turn the vacuum on and off power themicrokeratome. The vacuum and power for the ALK are provided integrallythrough the laser system L through two ports 306 and 308. Preferably, anurse will be stationed adjacent to the doctor and attach themicrokeratome when it is needed. The ports 306 and 308 can of course belocated elsewhere on the laser system L, but their integral natureassists in the operation. Further, the ALK system is coupled to theelectronics 202 for monitoring. For example, if the vacuum fails, onewould immediately wish to cease blade movement, because high speed blademovement is necessary to prevent binding with the lamellar flap as it istaken. Further, the ALK system can be further integrated and controlledthrough computer access via the computer system in the electronics 202.The computer system is preferably integrated to the electronics 202 andprovides control for various systems, including the display 110, thecontrol inputs 108, and the keyboard 106. Further, the computer systempreferably controls the eye tracking system, the aiming system, thelaser head 204 and the firing of the laser head 204. Further, thecomputer system preferably includes a remote disk drive slot 312, forexample for the insertion of a preprogrammed shot pattern, such as thatdescribed in assignee's co-pending U.S. patent application Ser. No.______entitled “Distributed Laser Surgery System” and filed concurrentlyherewith.

[0036] The computer system can be further integrated with the automatedlamellar keratoplasty system 300. The automated lamellar keratoplastysystem 300 typically provides a vacuum pressure output signal,microkeratome voltage and current output signals, as well as controlinputs. The computer system can both display the microkeratome voltageand current and vacuum pressure, and generate warning messages ordisable both the power source within the automated lamellar keratoplastysystem and the vacuum source within the automated lamellar keratoplastysystem should there be a failure. Further, the computer system can bedisposed between the automated lamellar keratoplasty system 300 and thefoot switches 119 and 121, so that the computer system itself controlsthe automated lamellar keratoplasty system 300 responsive to the footswitches 119 and 121.

[0037] Further, using the keyboard 106, the user in such a situationcould set the power level of the power source in the automated lamellarkeratoplasty system 300 and the vacuum pressure of the vacuum sourcewithin the automated lamellar keratoplasty system 300 using feedback onthe display 110 on a routine executing in the computer system of theelectronics 202.

[0038] In view of the foregoing discussion and figures, it will beappreciated that the system provides a compact excimer laser surgerysystem with a rotatable bed for patient convenience and for non-excimerlaser operation. Further, an integrated ALK system provides for theconvenient performance of laser in situ keratomileusis.

[0039] Finally, arrangement of components underneath the patient bedenclosure and patient bed, their arrangement next to the laser head,reduces the space taken by the system, thus providing for the moreefficient of clean room environments.

[0040] The foregoing disclosure and description of the invention areillustrative and explanatory thereof, and various changes in the size,shape, materials, components, circuit elements, wiring connections andcontacts, as well as in the details of the illustrated circuitry andconstruction and method of operation may be made without departing fromthe spirit of the invention.

1. A system for laser eye surgery, the system comprising: a laser headfor providing a laser beam suitable for removing tissue from an eye; apower supply connected to the laser head for powering the laser head; anaiming system for providing an optical path from said laser head and foraiming the laser beam along the optical path to the eye, said aimingsystem further comprising: a final beam directing portion extendinghorizontally over a patient in an operational position, the final beamdirecting portion directing the laser beam substantially perpendicularto the patient's eye when the patient is in the operational position; apatient bed positioned rotatably below the final beam directing portion,said patient bed rotatable from a first position wherein the patient isin the operational position below said final beam directing portion, toa second position in which the patient is moved away from below saidfinal beam directing portion, whereby the patient can easily sit upwithout striking his or her head against the final beam directingportion.
 2. The system of claim 1 , wherein when the patient is in anoperational position below said final beam directing portion, the eye ofthe patient is about one-half meter below said final beam directingportion.
 3. The system of claim 1 , wherein said bed is rotatable awayfrom below said final beam directing portion by about 30°.
 4. The systemof claim 1 , wherein said bed is rotatable about 90° into a secondoperational position in which non-laser surgery can be performed.
 5. Thesystem of claim 1 , wherein the laser head is an excimer laser.
 6. Thesystem of claim 5 , wherein the excimer laser is an argon fluoride laserproviding a laser beam of approximately 193 nanometers.
 7. The system ofclaim 1 further comprising a solenoid between the bed and a base for thebed, said solenoid locking the bed into position when the bed is in theoperational position.
 8. The system of claim 1 , wherein the bed isrotatable on a single bearing connected to the base of the bed.
 9. Alaser system for performing laser in situ keratomileusis, the lasersystem comprising: a laser head providing a laser beam for ablation ofstromal tissue; an aiming system providing an optical path from saidlaser head for the laser beam and for aiming the laser beam along theoptical path to the eye; a computer system coupled to said aiming systemand said laser head, said computer system controlling the firing of saidlaser head and the aiming system and displaying data on a display, saidcomputer system coupled to said automated lamellar keratoplasty systemand displaying vacuum and power data from said automated lamellarkeratoplasty system; an integrated automated lamellar keratoplastysystem comprising: a vacuum source for vacuum port for providing avacuum to a microkeratome source a power source for providing power to aport for providing power to the microkeratome.
 10. The system of claim 9further comprising: a patient bed disposed horizontally, and whereinsaid aiming system further comprises: a final beam directing portionextending horizontally over the patient bed, and wherein said final beamdirecting portion includes said vacuum port and said power port for easyaccess to a physician performing automated lamellar keratoplasty upon apatient on the patient bed.
 11. The system of claim 9 furthercomprising: a patient bed, said patient bed including: a foot rest withtwo foot switches coupled to the automated lamellar keratoplasty system,said foot switches controlling said vacuum source and said power source.12. The system of claim 9 , wherein said computer system furthercontrols said vacuum source and said power source of said automatedlamellar keratoplasty system responsive to said foot switches.
 13. Thesystem of claim 9 , wherein said computer system further provides inputfor a physician to set a vacuum level and a power level for said vacuumsource and said power source in the automated lamellar keratoplastysystem.
 14. A compact laser surgery system comprising: a patient bedenclosure with a patient surface and a patient height, said patient bedenclosure surrounding an open space; a laser gas container disposed insaid open space towards a first side of said patient bed; an electronicspackage for providing computer control disposed in said open spaceadjacent to said laser gas container towards a second side of saidpatient bed; a laser head located adjacent to said patient at a heightless than said patient height, said laser head connected to laser gascontainer for receiving laser gas and connected to said electronics forreceiving power.
 15. The system of claim 14 further comprising an aimingsystem providing an optical path from said laser head, said aimingsystem disposed perpendicularly upwards from the laser heard,transversely across from the laser head in an optical extension abovethe patient bed, the aiming system to provide the laser beamsubstantially perpendicular towards the eye of the patient on thepatient bed.
 16. The system of claim 14 , wherein the patient surfacerotates across the laser head and away from the optical extension. 17.The system of claim 14 further including cooling system componentsdisposed in said open space adjacent to said laser gas container towardssaid second side of said patient bed, but away from said electronics.18. The system of claim 17 , wherein power components are disposedbetween said cooling system components and said electronics.
 19. Thesystem of claim 14 , wherein said patient bed is mounted on the rollerswith stops, allowing said patient bed to be rolled away to provideaccess to said gas container and said electronics.